1. Field of the Invention
The present invention pertains to a method and apparatus for repairing flange connections including, without limitation, bolted pipe flange connections. More particularly, the present invention pertains to a clamp assembly for securing bolted pipe flange connection members together such as, for example, during repair or maintenance of said flange connection members or replacement of bolts or other flange components.
2. Brief Description of the Prior Art
Pipes and other tubular sections are frequently joined using mating flange connection assemblies. Such flange connection assemblies typically comprise substantially planar opposing plate-like members having aligned transverse bores. The mating plate-like flange members are joined, and then secured together using fasteners such as threaded bolts and mating nuts. Such bolts or other fasteners are used to provide compressive force to urge such pipe flange members toward each other and to secure said pipe flange members in place. In many cases, a plurality of such bolts or other fasteners is disposed in a substantially circular pattern through such mating flange members.
Frequently, one or more of said threaded bolts and/or nuts can become damaged due to weathering, oxidation and/or other factors. In such cases, it is frequently beneficial to remove and replace such damaged bolts/nuts. In other instances, said bolts and/or nuts are removed and replaced as part of a predetermined schedule or structured preventative maintenance program.
In some cases, said bolts and/or nuts can be unthreaded, separated and removed using wrenches or other tools. In other cases, the conditions of said bolts and/or nuts are so severely degraded or damaged that said bolts and/or nuts must be cut apart using welding torches, saws or other devices in order to facilitate removal from such mated flange members. Once removed, the existing/damaged bolts can then be replaced with new bolts, nuts or other fasteners.
Pipes or other tubular sections joined using flange connection assemblies often contain fluid(s), and said fluid(s) are frequently pressurized. As a result, flange connection assemblies must generally provide a fluid-tight pressure seal to contain such fluids and prevent leakage of the fluids from the interface between said mating flange members. A fluid pressure seal formed by a joined flange connection assembly can frequently be broken when one or more bolt fasteners are removed from said flange connection assembly. When such a seal breaks, fluid(s) contained within said flange connection assembly and related pipes/tubular goods can leak from said flange connection assembly, resulting in contamination of a surrounding environment and/or exposure of personnel to harmful, flammable or hazardous fluids.
In order to prevent such unwanted leakage or discharge of fluids, such pipe or tubular sections are frequently drained or evacuated of fluids before bolts or other fasteners are removed from a flange connection assembly. Unfortunately, fluid flow interruption and pipe draining process can be time consuming and expensive. For example, for flange assemblies located on oil and gas production facilities, shutting in of production, and purging of pipes and/or flow lines, can be an extremely expensive and disruptive process.
In certain circumstances, bolts can be cut or otherwise removed from a flange connection assembly without interrupting the flow of fluids through said flange connection assembly, and/or draining fluids from associated pipes/tubular goods, using a process commonly referred to as “hot bolting”. In such cases, an ancillary clamp or other external means can be used to compress and/or secure opposing flange members together in order to maintain a fluid-tight pressure seal across a flange connection assembly even when one or more bolts are loosened or removed. However, conventional means of securing opposing flange members together for this purpose generally suffer from a number of important limitations including, without limitation, devices that are bulky, expensive, and difficult to install and/or operate. Thus, there is a need for an inexpensive, effective and versatile means for temporarily securing opposing members of a flange connection assembly together, particularly during bolt removal and replacement operations.